Four Design Rules Four Design Rules

Four Design Rules • Java, Microservices, Cloud • @AltamuraClaudio • claudioaltamura Claudio Altamura

Claudio Altamura Four Design Rules Kent Becks Design Rules • Passes the tests • Reveals intention • No duplication • Fewest elements

Claudio Altamura Four Design Rules What's so special about it? • easy to remember • improves code in every language • helps to keep the design simple • leads to a good design

Claudio Altamura Four Design Rules What is a good design? • high cohesive • loosely coupled • expressive names

Claudio Altamura Four Design Rules Passes the Tests • the code must work • tests help to communicate the design • tests make refactoring safe

Claudio Altamura Four Design Rules Reveals Intention • code as easy as possible • expresses every idea • meaningful names • brings clarity • maximizes cohesion

Claudio Altamura Four Design Rules No Duplication • DRY • SPOT • everything should be said once • leads to a good design • minimize coupling

Claudio Altamura Four Design Rules Fewest Elements • what is not useful should be removed • fewest possible classes and methods • don't add code for future requirements • complexity makes code harder to modify

Claudio Altamura Four Design Rules Priority Reveals Intention Priority No Duplication Passes the Tests Fewest Elements

Claudio Altamura Four Design Rules Intention vs Duplication • doesn't matter which comes first • both rules help to redefine the code • these rules lead to a simple design • most problems are naming problems